1. Field of the Invention
This invention pertains to a device for stiffening workpieces of paper or the like and, in particular, to a device for stiffening tubular sections used in the manufacture of bags.
2. Description of Related Art
When collecting or additionally processing sections that have been severed from a paper web, the sections need to be stacked or transported. The flexibility or limberness of the paper sections can cause problems in properly positioned depositing or additional transporting of these paper sections.
In the manufacture of paper bags, paper webs are initially unwound from reels. The paper webs are placed on top of one another in a multilayered fashion. Subsequently, tubular webs are formed by folding in overlapping side parts and gluing together the overlapping regions. Tubular sections that are either stacked or deposited on a slat belt conveyor in imbricated fashion at high speeds are subsequently severed from these tubular webs. In order to prevent the tubular sections that were severed from the tubular web from assuming an oblique position and not exactly aligning with one another due to their limberness and/or flexibility while they are deposited on the slat belt conveyor, it is known to convey the tubular sections through cooperating disks that provide the tubular sections with an undulated profile. This undulated profile stiffens the tubular sections such that they are no longer able to bend or overturn about their lateral axes. However, the profiling disks that are usually arranged on both sides of the central longitudinal axis of the workpieces tend to laterally entrain the material of the tubular sections in an uncontrollable fashion. In this case, it is uncertain on which side the material is entrained. The lateral edges of the workpieces, therefore, may not be exactly aligned when the workpieces are deposited on the subsequently arranged slat belt conveyor in imbricated fashion.